Watts Bar actually is what it sounds like: a watering hole for light bulbs. It’s a nuclear reactor. And not just any nuclear reactor. As James Conca wrote in Forbes this week, it will be “the first nuclear unit to come online in the U.S. since its sister reactor, Watts Bar 1, came on line in 1996.” (Who knew nuclear reactors were female?) And, Conca reported, it should start operating next year.

What I found most striking about Conca’s account of Tennessee’s new nuclear arrival was this:

“Watts Bar 2 construction was halted in 1988 because of low electricity demand from the economic recession, as were most of the newly planned reactors across the country.”

This reactor may be the first of many new nuclear facilities in the U.S.: The Chicago Tribune reported that, according to EPA administrator Gina McCarthy, new state carbon emissions targets are designed in part to incentivize nuclear power.

With nuclear potentially playing a bigger role in America’s energy future, it’s a good time to answer some basic questions.

(Actually the one in the lower left corner of the country, in San Diego county, has been decommissioned and is no longer operational – the map needs updating!)

Most of them are located in the Southeast, Mid-Atlantic, and Midwest, with very few in the West, and none in our Inside Energy focus states Colorado, North Dakota and Wyoming.

How much of U.S. electricity comes from nuclear?

It fluctuates, but generally around one-fifth of U.S. electricity is generated by a nuclear reactor. Here’s a graph from the EIA (view an interactive version here) showing the total nuclear generation (blue line) and the percent of U.S. electricity that comes from nuclear (brown line):

Related Series

Energy is a broad and confusing topic. In this series, Inside Energy reporters de-mystify the wonkiness that dominates so much of the energy conversation, through answering your questions, as well as questions we encounter in the field. What's your energy head scratcher? Submit it at ask.insideenergy.org, e-mail it to us at Ask@insideenergy.org, or tweet it to @InsideEnergyNow with hashtag #MyEnergyQuestion.

Jordan Wirfs-Brock was Inside Energy's first data journalist, based in Colorado. Now she's living in the San Juan Islands, but is still helping us out. When she's not wrangling data, she enjoys running up and down mountains, doodling, playing board games and brewing beer.

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